Male-produced sex pheromone of the stink bug Edessa meditabunda.

Edessa meditabunda is a secondary pest within the piercing-sucking stink bug complex that attacks soybean crops in Brazil. The behavioral responses of males and females to aeration extracts from conspecifics suggested the presence of a male-produced sex pheromone. Gas chromatographic (GC) analysis of male and female aeration extracts revealed the presence of two male-specific compounds in a ratio of 92:8. Gas chromatographic -electroantennographic detection (GC-EAD) assays indicated that the major component is bioactive for females, supporting the behavioral data. Analysis of the mass and infrared spectra of the male-specific compounds suggested that they were both methyl-branched long-chain methyl esters. On the basis of the mass spectra of the respective hydrocarbons obtained by micro derivatizations, the structures of these methyl esters were proposed to be methyl 4,8,12-trimethylpentadecanoate (major) and methyl 4,8,12-trimethyltetradecanoate (minor). An 11 step synthetic route that was based on a sequence of Grignard reactions, starting from cyclopropyl methyl ketone, was developed to obtain synthetic standards with a 7.9 % overall yield for the major compound and a 9.9 % yield for the minor. The synthetic standards co-eluted with the natural pheromones on three different GC stationary phases. Y-tube olfactometer assays showed that the synthetic standards, including the major compound alone and a mixture of the major and minor compounds in the proportion found in natural extracts, were strongly attractive to females.

The male-produced sex pheromone of the true bug, Phthia picta, is an unusual hydrocarbon.

Phthia picta is part of a complex of true bugs (Heteroptera) in Brazil that attack tomatoes, being particularly damaging because nymphs and adults feed on both leaves and fruit. Gas chromatography (GC) of aeration extracts of adult males vs. females revealed the presence of a male-specific compound. GC-electroantennographic detector experiments indicated that the antennae of females are highly sensitive to this male-specific compound. GC-mass spectrometry and GC-FTIR analyses suggested a methyl branched hydrocarbon structure for this compound. After synthesis of three different proposed structures, the natural product was indentified as 5,9,17-trimethylhenicosane, which was strongly attractive to females in Y-tube olfactometer bioassays. Analysis of dissected body parts of adults revealed that the pheromone is produced in the lateral accessory glands of the metathoracic scent gland of males only.